Usually, the only thing for St. Patrick's day is a four-leaf clover and Lucky K.K.. But in City Folk you can get a leprechaun hat called the shamrock hat! Start your game with Lucky K.K. playing on March 17th, St. Patrick's Day, and Pelipper will be outside with a letter from Nintendo, saying that it should prevent pinching. It is possible it only happens through Wi-Fi Connection.